


Joining

by missy520



Category: Castle
Genre: Open Relationships, Oral Sex, Prompt Fill, Threesome - F/F/M
Language: English
Status: Completed
Published: 2015-08-12
Updated: 2015-08-12
Packaged: 2018-04-14 08:55:08
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,267
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4558488
Author URL: https://archiveofourown.org/users/missy520/pseuds/missy520
Summary: <blockquote class="userstuff">
              <p>A sort of sequel to "Watching". </p>
<p>From a prompt from Blackwing:<br/>If I may offer a third option - instead of an alternate version of the story, a sort of a sequel. You open up with an altered version of the last couple of paragraphs of Watching - one where Alexis indicates that she is aware of Caskett's open marriage situation and even eager to make use of it, Kate still goes to bed intending to sleep and this time instead of thinking how Castle can't ever know of the evenings adventure she thinks of how much he will enjoy hearing about it. And then she can't sleep, either because these thought get her worked up all over again or because Alexis makes no effort at all to be quiet so Kate decides that if she can't sleep she might as well get some fun out of it and goes up to join.</p>
<p>Disclaimer: I don't own Castle</p>
            </blockquote>





	Joining

**Author's Note:**

> As you can tell from the prompt, I changed the ending of "Watching" a little and made this a continuation of that story. Thanks to Blackwing to nudging me into it!
> 
> Please note: Alexis and Kate have sex in this story; I know that bothers some people. If it bothers you, please back away now. I understand. No hard feelings.

“So is he done or will there be more action?” Kate chuckled as she said it. “Or do you plan to move this upstairs?” 

“Well, he usually can do this for hours. He’s amazing that way. But I think we’ll move it upstairs. You’re welcome to keep watching if you want; Sam did seem to enjoy having you here,” Alexis smirked at Kate. “Or maybe you’d like to join us, hmm?” Alexis had been aware of the open relationship Kate and Rick had ever since she had decided to surprise them and instead got the surprise of her life – Rick had been balls deep in another woman while Kate was fingering herself nearby. Alexis had been upset and then intrigued as Kate told her everything. Maybe this was her chance to be kind of a part of the open relationship. 

“No, thank you. But thanks for the orgasm. I should be able to sleep now,” Kate replied. “Do you plan to sleep here tonight?” As she said this, Kate pulled her panties and sleep shorts back up. 

“Yeah, we’ll probably sleep here, but we’re going to leave early too. I’m going to crash in Sam’s dorm room because I need to hit the library. We won’t be here for breakfast!” As soon as she said this, Sam came back in the room, and Alexis went over to Kate; they hugged and kissed each other on the cheek. Then Alexis took Sam by the hand, and led him upstairs. 

Poor Sam still looked a bit shell shocked, Kate thought as she made her way back to her bedroom. He had no idea this was going to happen. Well, it’s not like she planned it either. But she had learned to go with the flow ever since meeting Rick Castle. And then she giggled. Someday, she might share this one with Rick! She could imagine his reaction to it. She washed up and got into bed. 

And did not fall asleep. She couldn’t believe she was tossing and turning again; usually having an orgasm was like a glass of warm milk. Maybe it was the thought of watching Alexis and Sam some more; maybe it was the fact that she hadn’t had sex in two weeks; maybe it was the fact that Sam’s cock looked really nice and it seemed that he knew how to use it. And now, she can kinda hear Alexis – is she being loud on purpose? Did they leave the door open in their haste to fuck? Maybe if she put her pillow over her head….shit, that didn’t work when she was six, it’s sure as hell not going to work now. She may as well face it, she’s still horny. She wants to have sex with Sam and maybe even have sex with Alexis. 

Once that thought went through her head, she knew she longer had any choice. She got out of bed, and walked upstairs to Alexis’s room. They had left the door open, and she could hear the two of them moan. She walked in and watched them. They were doing it missionary style, so she had a lovely view of Sam’s tight ass clenching as he drove into Alexis. She wanted to feel that ass as he drove into her. She decided to get undressed; that way, she’d be ready whenever they finished this round. But she loved to watch people have sex too, so this was foreplay for her. She sat in the chair in the corner, and spread her legs. She could feel how wet she was, and she used that moisture to lubricate her fingers. She didn’t go slowly; she just thrust three fingers inside her pussy. She used her thumb to press down on her bundle of nerves. She went back to watching Alexis and Sam and saw that they were changing position, and wondered what they were doing next. 

As Sam pulled out and got off Alexis, Kate could see his dick was still hard. He removed the condom and disposed of it. He helped Alexis off the bed, and they kissed as they stood at the side of the bed. After they broke off the kiss, Alexis noticed Kate in the chair, and laughed. “Hey, Sam, we have a visitor!” Sam turned and saw Kate, and she could swear his cock stood up a little more. No more shock for him. He turned his head to look at Alexis and she nodded her head in Kate’s direction. Sam walked over to Kate, and tugged on her hand. She stood up and he walked Kate to the bed, and over to Alexis. Kate and Alexis kissed while Sam went to lie down in the bed, his hand on his cock, slowly stroking. Alexis put her lips close to Kate’s ear and murmured, “Go fuck him, Kate. I know you want to. Just think of what Dad will do when you tell him you fucked my 21 year old boyfriend,” and then Alexis took the lobe of Kate’s ear between her teeth and bit down. Then she licked it to soothe the pain.

Kate shuddered with arousal. Looking at Sam and his cock helped her make her decision. She climbed up on the bed, crawling over to Sam. He moved his hand off his cock, and Kate didn’t hesitate – she kissed the tip, and then licked it up and down. Alexis had climbed up on the bed, too, and put her hands on Sam’s balls and tickled. Kate sucked on his cock, and moved her tongue around it. But she needed it to be inside her, and soon. She removed it from her mouth, looked at Alexis, and said, “Condom?” Alexis had anticipated this, and handed it to Kate. Kate sat up and made sure the other two were watching as she ripped the package open and put it on Sam – she didn’t use any fancy maneuvers since she didn’t want to waste any time – and taking his cock in hand, she guided it to her entrance. Then she impaled herself on it. She and Sam groaned together. Damn, his cock felt fantastic. Kate rode his cock with abandon. 

Alexis watched her boyfriend and her stepmother fucking each other and knew she needed to be a part of the action. She moved over to be closer to Sam, and put her knees on either side of his face and sat on his face. Sam didn’t slow down his fucking but he started licking everywhere he could reach. Kate and Alexis couldn’t help it; they had to kiss each other. 

Kate always loved being on top, and this was amazing. She could feel every ridge of Sam’s hard cock as she rode it. Sam started thrusting upwards too, and then Alexis kissed her again. Kate and Alexis both moaned. Kate could tell Alexis loved the attention Sam was giving to her pussy. Maybe she’d get to know how great it felt to sit on his face while his tongue went everywhere. She touched Alexis’s breasts. They were so soft and they felt great; her nipples were so responsive to each of Kate’s touches. Then Alexis reached over to rub Kate’s breasts. 

Alexis needed to breathe, so she stopped kissing Kate but she moved her hands to Kate’s magnificent ass. Kate had had some mind blowing sex before – hell, she’d even had a threesome before – but this was something else. Wait until she shared this with Castle. And with that thought, she came with a scream which set off Alexis and then Sam’s cock erupted. The three of them collapsed in a sweaty heap. 

“Fuck, I think the two of you wore me out. I need a break,” Sam laughed. Alexis and Kate giggled a little.

“Are you worn out, Kate?” Alexis smirked as she said it. “I know I’m not.” Kate grinned at her. They were on their sides, face to face on the bed, and Alexis reached out a hand, and put it on Kate’s breast. 

The atmosphere in the room changed instantly. Neither woman smiled but Kate could feel her pulse race. Should she reciprocate? But when Alexis tugged on her nipple, all thoughts fled from her mind and she moved closer and kissed Alexis. Kate rolled them over so Alexis was on the bottom. They continued to kiss each other as Kate moved her hands to Alexis’ pussy. One finger parted her folds and discovered how wet she was. Kate gathered up the moisture, and spread it everywhere. She broke off the kiss, smiled at Alexis and slowly moved down her body. She had one mission: to taste Alexis. As soon as her face was close to her pussy, she used her hands to open it as much as she could. 

Kate licked her pussy with tiny licks that teased Alexis. Alexis started to move her hips so Kate stopped licking her for a minute. When Alexis groaned in frustration, Kate moved an arm to hold her in place, and then swept her tongue all around her folds. Alexis squirmed as Kate’s tongue found her clit and stayed focused on her clit. Then she went back to licking everywhere, and even inserted a few fingers inside Alexis. Kate was searching for her g-spot; she wondered if Alexis had ever experienced a g-spot orgasm. Almost as soon as Kate had that thought, she found it, and tickled it. Alexis screamed as she came, and she squirted all over Kate’s hand. 

Sam had been on his back, idly stroking his cock while Kate made love to Alexis, but when he realized she was close to coming, he sat up and watched. And when he saw her squirt, he nearly screamed too. “Damn, Alexis, that was hot. Fucking hot! And I’m not worn out anymore – my cock is totally awake now! I need to put this cock in one of you or maybe the both of you as soon as I can,” the young man said. Kate reached over to get another condom, and this time, she slowly ripped open the package, and then slowly rolled it down his erection. Alexis had recovered quickly from her orgasm, and she watched Kate cover Sam’s prick. All three of them groaned together. 

Sam directed them into a new position. “Kate, could you lie on your back? And Alexis, I know it might be a bit uncomfortable, but could you lie on you back onto of Kate? Kate, maybe you could hold Alexis?”

Kate realized what Sam was doing – he’d probably seen a scene like this in a porno and was trying to re-enact it. “Relax Alexis; I think I get what Sam wants. C’mon, and I’ll help you,” Kate’s calm voice and big smile helped Alexis decide to go along with this. While the ladies were arranging themselves to Sam’s wishes, he was stroking his latex covered penis. Kate had her arms around Alexis’s waist, and once Alexis was settled, moved her hands to her breasts. Sam noticed what Kate was doing and got up on his knees in front of them.

He took his cock and ran it through Alexis’s folds, and then entered her. Alexis wailed as he moved in and out and Kate’s fingers were playing with her nipples. She whimpered as Sam pulled out, but then she realized what he was doing – he was now running his cock through Kate’s wet pussy and then he entered her. He thrust into her a few times, pulled out and entered Alexis again. 

Kate had to admit this was the most interesting threesome she’d ever be a part of. She’d have to get Castle to try this position; he’d probably love it. She knew she was enjoying it; Alexis was moving her ass on Kate’s pelvis, and Sam was keeping up a lovely rhythm with his thrusts. 

Alexis wasn’t thinking anything; she was incapable of thought right now, she was all about feelings. How Kate’s fingers felt on her nipples, how Kate’s nipples were burning little points into her back, how Sam’s fucking was hitting her in all the good spots. They were going to have to do this again, very soon!

Kate realized Sam was just about to come, and she increased the pressure on Alexis’s nipples. Sam pulled out of Alexis and thrust once into Kate, and then he pulled out and removed the condom. His come flew out of the end of his cock, and landed all over Alexis. Kate smeared some of it into her breasts. Sam reached down and started rubbing Kate’s pussy and then Alexis’s. When he returned to Kate’s, he pinched her clit between two fingers and that was all she needed to come. Then he repeated the action on Alexis’s clit and she came too. 

Alexis rolled off Kate and she just lay on the bed panting. “Damn that was amazing, I feel fucking amazing right now. But I also need a shower!” and with that, Sam helped her get off the bed. She turned to Kate and said, “Want to join us? Just a shower, nothing else,” she giggled. Kate nodded her head yes, and the three of them got cleaned off. The three of them climbed into bed together, with Alexis cuddled between Sam and Kate. 

The next morning, Kate woke up when Alexis kissed her cheek. “Hey, Kate, we’re leaving. Thanks for a fun night; we’ll have to do that again sometime!” Kate smiled and turned over and went right back to sleep. Multiple orgasms and a night of crazy sex can do that to a person.


End file.
